Detect BIOS or UEFI / EFI from Windows PE

To detect whether you’re computer is running with a BIOS or UEFI, type the following command:

reg query HKLM\System\CurrentControlSet\Control /v PEFirmwareType 

The following results codes are available:

  • 0x1 = BIOS
  • 0x2 = (U)EFI

Depending on the BIOS or EFI the hard disk partitioning will use MBR (with BIOS) or GPT (with UEFI) when installing Windows 7 /8.

More information about the difference between GPT and MBR can be found on the Wiki pages:

GPT = GUID Partition Table (http://en.wikipedia.org/wiki/GUID_Partition_Table)
MBR = Master Boot Record (https://en.wikipedia.org/wiki/Master_boot_record)